What is Metamod: Source:
Metamod: Source is a server plug-in that can intercept activities between the server and the client to be used as a base “hook” for use in other plug-ins. This means other plug-ins can be loaded onto MM:S and use “hooks” under one roof. It’s also a small plug-in manager, you can enable and disable installed plug-ins with a few simple commands.
For more information visit their website at http://www.sourcemm.net

How to get Metamod: Source:
MM:S can simply be downloaded as either an installer (.exe) or as a package (.zip), for this tutorial we need the package (.zip).
There is one installer and there are two packages on the download page ( http://www.sourcemm.net/?go=downloads ). The fist package is for games based on the original Source Engine (CS:S, DOD:S, HL2M etc.), the second package is for the new Source engine (TF2 and other Orange Box games). In this tutorial I will be installing MM:S on a CS:S server, so I download the first package. Note: The installation process is exactly the same for all games, don’t worry.

The installation:
Now that you have the package downloaded above, we can start with the actual installation. Start by extracting the package somewhere on your computer, you should get the following out of the package:

These files have to be placed in the SRCDS\<modfolder>\, for me it’s C:\SRCDS\cstrike\, I simply copy the addons folder and upload it to my server’s cstrike folder.
My cstrike folder on the server now has an addons folder with MM:S in it.
This is what it should look like:

Now that all the files are in place, the only thing that’s left to do is make MM:S load when the server starts. This has to be done in a file called “gameinfo.txt”, It’s located in the main modfolder (So for me that’s cstrike).
Open up “gaminfo.txt” and you will find something that looks a little more complicated, but don’t worry we only have to edit one line of the file.
Find the following lines:

Code:

SearchPaths
{
Game |gameinfo_path|.
Game cstrike
Game hl2
}
}
}

Now add a line “GameBin |gameinfo_path|addons/metamod/bin”
It should look like this:

Now save the file, that’s it! Metamod:Source should now be installed on your server.

How to check if Metamod: Source is running:
Finally, check if the plug-in is actually running.
To do this start up your server, when it’s all started type “meta version” in the console. Note: If you do not have access to the console, use the RCon protocol to send the command through RCon, this can be achieved either by joining the game as a client or using programs like HLSW.
The response should be something like this (If you get an “unknown command” you did something wrong above, run through the steps again):

I used gameinfo for years, and every now and then after updating, i was driving myself mad trying to figure out why plugins weren't loading... Then I remembered that damn gameinfo.txt got overwritten!! But I guess if you use a script for updating your servers, as I do now, you just make your gameinfo.txt elsewhere and add a line to the update script to copy it over after the update...